Effect of elevated CO2 on monoterpene emission of young Quercus ilex trees and its relation to structural and ecophysiological parameters |
| |
| Authors: | Staudt M Joffre R Rambal S Kesselmeier J |
| |
| Institution: | DREAM unit, Centre d'Ecologie Fonctionelle et Evolutive CNRS, 1919 Route de Mende, 34293 Montpellier cedex 5, France. |
| |
| Abstract: | We investigated growth, leaf monoterpene emission, gas exchange, leaf structure and leaf chemical composition of 1-year-old Quercus ilex L. seedlings grown in ambient (350 microl l(-1)) and elevated (700 microl l(-1)) CO2 concentrations (CO2]). Monoterpene emission and gas exchange were determined at constant temperature and irradiance (25 degrees C and 1000 micromol m(-2) s(-1) of photosynthetically active radiation) at an assay CO2] of 350 or 700 microl l(-1). Measurements were made on intact shoots after the end of the growing season between mid-October and mid-February. On average, plants grown in elevated CO2] had significantly increased foliage biomass (about 50%). Leaves in the elevated CO2] treatment were significantly thicker and had significantly higher concentrations of cellulose and lignin and significantly lower concentrations of nitrogen and minerals than leaves in the ambient CO2] treatment. Leaf dry matter density and leaf concentrations of starch, soluble sugars, lipids and hemi-cellulose were not significantly affected by growth in elevated CO2]. Monoterpene emissions of seedlings were significantly increased by elevated CO2] but were insensitive to short-term changes in assay CO2]. On average, plants grown in elevated CO2] had 1.8-fold higher monoterpene emissions irrespective of the assay CO2]. Conversely, assay CO2] rapidly affected photosynthetic rate, but there was no apparent long-term acclimation of photosynthesis to growth in elevated CO2]. Regardless of growth CO2], photosynthetic rates of all plants almost doubled when the assay CO2] was switched from 350 to 700 microl l(-1). At the same assay CO2], mean photosynthetic rates of seedlings in the two growth CO2 treatments were similar. The percentage of assimilated carbon lost as monoterpenes was not significantly altered by CO2 enrichment. Leaf emission rates were correlated with leaf thickness, leaf concentrations of cellulose, lignin and nitrogen, and total plant leaf area. In all plants, monoterpene emissions strongly declined during the winter independently of CO2 treatment. The results are discussed in the context of the acquisition and allocation of resources by Q. ilex seedlings and evaluated in terms of emission predictions. |
| |
| Keywords: | |
| 本文献已被 PubMed 等数据库收录！ |
|
